Delay and related circuits are generally known in the art. Examples of such circuits are as follows:
Japanese Pat. No. 60-33732 discloses a delay circuit whose delay time is stable against power supply variations and temperature fluctuations. This circuit varies an injector current from a constant current supply (an operational amplifier) to obtain changes in the delay time of the circuit.
U.S. Pat. No. 3,346,746 discloses a monostable multivibrator triggered by an OR-gate which receives a plurality of inputs. In addition, the pulse time of the multivibrator is in part controlled by a variable timing network in response to the particular input which input triggered the multivibrator.
U.S. Pat. No. 3,753,012 discloses a time delay generator which provides a plurality of precise time delays following a trigger action.
U.S. Pat. No. 3,675,133 discloses an apparatus for independently varying, by preselected amounts, the position of pulse edges by the use of a plurality of variable delay means.
U.S. Pat. No. 3,558,924 discloses a circuit having a plurality of input signals with corresponding time-delayed independent output signals.
Other references which are related to the general field of delay circuits are: U.S. Pat. Nos. 2,964,708, 3,102,208, 4,140,927, 4,587,441 and 4,638,188, and Japanese Patent Nos. 57-99029 and 57-131126.
In designing delay circuits, it is important that the delay characteristics of the circuit be as accurate a possible.
Further, it is necessary to consider process tolerances, temperature differentials and changes in the power supply of the delay circuit, all of which are factors in the reliability or accuracy of a delay circuit.